Robin by Frances Hodgson Burnett

The swiftness of the process by which the glowing little Miss Lawless, at whom people had found themselves involuntarily looking so often, changed from a rose of a girl into something strangely like a small waxen image which walked, called forth frequent startled comment. She was glanced at even oftener than ever.

"Is she going into galloping consumption? Her little chin has grown quite pointed and her eyes are actually frightening," was an early observation. But girls who are going into galloping consumption cough and look hectic and are weaker day by day and she had no cough, nor was she hectic and, though it was known that Dr. Redcliff saw her frequently, she insisted that she was not ill and begged the Duchess to let her go on with her work.